Scroll compressor

ABSTRACT

The scroll compressor is provided that may include a casing including a rotational shaft; a discharge cover fixed inside of the casing to partition the inside of the casing into a suction space and a discharge space; a back pressure plate that defines a back pressure chamber that accommodates a refrigerant, a floating plate to define the back pressure chamber together with the back pressure plate, the floating plate including a contact or rib capable of contacting the discharge cover, and a coating layer that defines an outer surface of the contact. The discharge cover may have a first hardness value, the floating plate may have a second hardness value, and the coating layer may have a third hardness value. The third hardness value may be less than the first hardness value and greater than the second hardness value.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2014-0053652, filed in Korea on May 2, 2014, which is hereby incorporated by reference in its entirety.

BACKGROUND

1. Field

A scroll compressor is disclosed herein.

2. Background

A scroll compressor is a compressor that includes a fixed scroll having a spiral wrap, and an orbiting scroll that revolves with respect to the fixed scroll, that is, a compressor in which the fixed scroll and the orbiting scroll are engaged with each other. The orbiting scroll revolves with respect to the fixed scroll, thereby reducing a volume of a compression chamber, which is formed between the fixed scroll and the orbiting scroll according to an orbiting motion of an orbiting scroll, thus increasing a pressure of a fluid, which is then discharged through a discharge hole formed in a central portion of the fixed scroll.

In the scroll compressor, suction, compression, and discharge of a fluid are successively performed while the orbiting scroll revolves. Accordingly, a discharge valve and a suction valve may be unnecessary in principle. Also, as a number of components of the scroll compressor is less in comparison to other types of compressors, the scroll compressor may be simplified in structure and rotate at a high speed. Also, as a variation in torque required for compression is less, and suction and compression successively occur, a relatively small amount of noise and vibration may occur.

A scroll compressor including a back pressure discharge unit or device is disclosed in Korean Patent Registration No. 10-1378886 (hereinafter, the “prior document”), which is hereby incorporated by reference. The scroll compressor according to the prior document includes a back pressure chamber assembly defining a back pressure chamber. The back pressure chamber assembly includes a back pressure plate and a floating plate. A sealing end is disposed on an upper end of an inner space of the floating plate. The sealing end contacts a bottom surface of a discharge cover to seal the inner space so that discharged refrigerant does not leak into a suction space, but rather, is discharged into a discharge space.

However, according to the prior document, the sealing end of the floating plate continuously collides with a discharge cover while the scroll compressor operates. In this case, the sealing end of the floating plate colliding with the discharge cover may be worn out, allowing the suction space to communicate with the discharge space. As a result, the scroll compressor may operate abnormally.

Also, according to the prior document, it is necessary to quickly space the floating plate from the discharge cover. This is done for a reason in which an equilibrium pressure reaching time within the compressor is reduced, reducing a re-operating time of the compressor when the floating plate is quickly spaced apart from the discharge cover.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements, and wherein:

FIG. 1 is a cross-sectional view of a scroll compressor according to an embodiment;

FIG. 2 is a partial exploded cross-sectional view of the scroll compressor of FIG. 1;

FIG. 3 is a partial cross-sectional view of the scroll compressor of FIG. 1;

FIG. 4 is a view illustrating a bottom surface of a back pressure plate according to an embodiment;

FIG. 5 is a graph illustrating a variation in abrasion depending on a thickness of a coating layer according to an embodiment;

FIG. 6 is a perspective view of a fixed scroll according to an embodiment;

FIG. 7 is a partial view of an orbiting scroll according to an embodiment;

FIG. 8 is a cross-sectional view illustrating a state in which the fixed scroll and the orbiting scroll are coupled to each other according to an embodiment;

FIGS. 9A to 9C are views illustrating relative positions of an intermediate pressure discharge hole of the fixed scroll and a discharge guide of the orbiting scroll while the orbiting scroll revolves; and

FIG. 10 is a partial cross-sectional view of a scroll compressor according to another embodiment.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings. Where possible, like reference numerals have been used to indicate like elements, and repetitive disclosure has been omitted.

In the following detailed description of embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is understood that other embodiments may be utilized and that logical structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope. To avoid detail not necessary to enable those skilled in the art to practice the embodiments, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense.

Also, in the description of embodiments, terms such as first, second, A, B, (a), (b) or the like may be used herein when describing components of the present invention. Each of these terminologies is not used to define an essence, order or sequence of a corresponding component but used merely to distinguish the corresponding component from other component(s). It should be noted that if it is described in the specification that one component is “connected,” “coupled” or “joined” to another component, the former may be directly “connected,” “coupled,” and “joined” to the latter or “connected”, “coupled”, and “joined” to the latter via another component.

FIG. 1 is a cross-sectional view of a scroll compressor according to an embodiment. FIG. 2 is a partial exploded cross-sectional view of the scroll compressor of FIG. 1. FIG. 3 is a partial cross-sectional view of the scroll compressor of FIG. 1. FIG. 4 is a view illustrating a bottom surface of a back pressure plate according to an embodiment.

Referring to FIGS. 1 to 4, a scroll compressor 100 according to an embodiment may include a casing 110 having a suction space S and a discharge space D. In detail, a discharge cover 105 may be disposed in or at an inner upper portion of the casing 110. An inner space of the casing 110 may be partitioned into the suction space S and the discharge space D by the discharge cover 105. An upper space of the discharge cover 105 may be the discharge space D, and a lower space of the discharge cover 105 may be the suction space S. A discharge hole 105 a, through which a refrigerant compressed to a high pressure may be discharged, may be defined in an approximately central portion of the discharge cover 105.

The scroll compressor 100 may further include a suction port 101 that communicates with the suction space S, and a discharge port 103 that communicates with the discharge space D. Each of the suction port 101 and the discharge port 103 may be fixed to the casing 101 to allow the refrigerant to be suctioned into the casing 110 or discharged outside of the casing 110.

A motor may be disposed in the suction space S. The motor may include a stator 112 coupled to an inner wall of the casing 110, a rotor 114 rotatably disposed within the stator 112, and a rotational shaft 116 that passes through a central portion of the stator 114.

A lower portion of the rotational shaft 116 may be rotatably supported by an auxiliary bearing 117 disposed on or at a lower portion of the casing 110. The auxiliary bearing 117 may be coupled to a lower frame 118 to stably support the rotational shaft 116.

The lower frame 118 may be fixed to the inner wall of the casing 110, and an upper space of the lower frame 118 may be used as an oil storage space. Oil stored in the oil storage space may be transferred upward by an oil supply passage 116 a defined in the rotational shaft 116 and uniformly supplied into the casing 110. The oil supply passage 116 a may be eccentrically disposed toward one side of the rotational shaft 116, so that the oil introduced into the oil supply passage 116 a may flow upward by a centrifugal force generated by rotation of the rotational shaft 116.

The scroll compressor 100 may further include a main frame 120. The main frame 120 may be fixed to the inner wall of the casing 110 and disposed in the suction space S.

An upper portion of the rotational shaft 116 may be rotatably supported by the main frame 120. A main bearing 122 that protrudes in a downward direction may be disposed on a bottom surface of the main frame 120. The rotational shaft 116 may be inserted into the main bearing 122. An inner wall of the main bearing 122 may function as a bearing surface so that the rotational shaft 116 may smoothly rotate.

The scroll compressor 100 may further include an orbiting scroll 130, and a fixed scroll 140. The orbiting scroll 130 may be seated on a top surface of the main frame 120.

The orbiting scroll 130 may include an orbiting head plate 133 having an approximately disk shape and disposed on the main frame 120, and an orbiting wrap 134 having a spiral shape and extending from the orbiting head plate 133. The orbiting head plate 133 may define a lower portion of the orbiting scroll 130 and function as a main body of the orbiting scroll 130, and the orbiting wrap 134 may extend in an upward direction from the orbiting head plate 133 to define an upper portion of the orbiting scroll 130. The orbiting wrap 134 together with a fixed wrap 144 of the fixed scroll 140 may define a compression chamber. The orbiting scroll 130 may be referred to as a “first scroll”, and the fixed scroll 140 may be referred to as a “second scroll”.

The orbiting head plate 133 of the orbiting scroll 130 may revolve in a state in which the orbiting head plate 133 is supported on the top surface of the main frame 120. An Oldham ring 136 may be disposed between the orbiting head plate 133 and the main frame 120 to prevent the orbiting scroll 130 from revolving. Also, a boss 138, into which the upper portion of the rotational shaft 116 may be inserted, may be disposed on a bottom surface of the orbiting head plate 133 of the orbiting scroll 130 to easily transmit a rotational force of the rotational shaft 116 to the orbiting scroll 130.

The fixed scroll 140 engaged with the orbiting scroll 130 may be disposed on the orbiting scroll 130. The fixed scroll 140 may include a plurality of coupling guides 141, each of which may define a guide hole 141 a.

The orbiting scroll 100 may further includes a guide pin 142 inserted into the guide hole 141 a and disposed on a top surface of the main frame 120, and a coupling member 145 a inserted into the guide pin 142 and fitted into an insertion hole 125 of the main frame 120.

The fixed scroll 140 may include a fixed head plate 143 having an approximately disk shape, and the fixed wrap 144 that extends from the fixed head plate 143 toward the orbiting head plate 133 and engaged with the orbiting wrap 134 of the orbiting scroll 130. The fixed head plate 143 may define an upper portion of the fixed scroll 140 and function as a main body of the fixed scroll 140, and the fixed wrap 144 may extend in a downward direction from the fixed head plate 143 to define a lower portion of the fixed scroll 140. The orbiting head plate 133 may be referred to as a “first head plate”, and the fixed head plate 143 may be referred to as a “second head plate”. The orbiting wrap 134 may be referred to as a “first wrap”, and the fixed wrap 144 may be referred to as a “second wrap”.

An end of the fixed wrap 144 may be disposed to contact the orbiting head plate 133, and an end of the orbiting wrap 134 may be disposed to contact the fixed head plate 143. The fixed wrap 144 may disposed in a predetermined spiral shape, and a discharge hole 145, through which the compressed refrigerant may be discharged, may be defined in an approximately central portion of the fixed head plate 143. A suction hole (see reference numeral 146 of FIG. 5), through which the refrigerant within the suction space S may be suctioned, may be defined in a side surface of the fixed scroll 140. The refrigerant suctioned through the suction hole 146 may be introduced into the compression chamber defined by the orbiting wrap 134 and the fixed wrap 144.

In detail, the fixed wrap 144 and the orbiting wrap 134 may define a plurality of compression chambers. Each of the plurality of compression chambers may be reduced in volume while revolving and moving toward the discharge hole 145 to compress the refrigerant. Thus, the compression chamber, which is adjacent to the suction hole 146, of the plurality of compression chambers may be minimized in pressure, and the compression chamber that communicates with the discharge hole 145 may be maximized in pressure. Also, the compression chamber between the above-described compression chambers may have an intermediate pressure that corresponds to a pressure between a suction pressure of the suction hole 146 and a discharge pressure of the discharge hole 145. The intermediate pressure may be applied to a back pressure chamber BP, which will be described hereinbelow, to press the fixed scroll 140 toward the orbiting scroll 130.

An intermediate pressure discharge hole 147 that transfers the refrigerant of the compression chamber having the intermediate pressure to the back pressure chamber BP may be defined in the fixed head plate 143 of the fixed scroll 140. That is, the intermediate pressure discharge hole 147 may be defined in one portion of the fixed scroll 140 so that the compression chamber that communicates with the intermediate pressure discharge hole 147 has a pressure greater than the suction pressure in the suction space S and less than the discharge pressure in the discharge space D. The intermediate pressure discharge hole 147 may pass through the fixed head plate 143 from a top surface to a bottom surface of the fixed head plate 143.

A back pressure chamber assembly 150 and 160 disposed above the fixed scroll 140 to define the back pressure chamber may be disposed on the fixed scroll 140. The back pressure chamber assembly 150 and 160 may include a back pressure plate 150, and a floating plate 160 separably coupled to the back pressure plate 150. The back pressure plate 150 may be fixed to an upper portion of the fixed head plate 143 of the fixed scroll 140.

The back pressure plate 150 may have an approximately annular shape with a hollow and include a support 152 that contacts the fixed head plate 143 of the fixed scroll 140. An intermediate pressure suction hole 153 that communicates with the intermediate pressure discharge hole 147 may be defined in the support 152. The intermediate pressure suction hole 153 may pass through the support 152 from a top surface to a bottom surface of the support 152.

A second coupling hole 154 that communicates with the first coupling hole 148 defined in the fixed head plate 143 of the fixed scroll 140 may be defined in the support 152. The first coupling hole 148 and the second coupling hole 154 may be coupled to each other by a coupling member (not shown).

The back pressure plate 150 may include a plurality of walls 158 and 159 that extend in an upward direction from the support 152. The plurality of walls 158 and 159 may include a first wall 158 that extends in the upward direction from an inner circumferential surface of the support 152 and a second wall 159 that extends in the upward direction from an outer circumferential surface of the support 152. Each of the first and second walls 158 and 159 may have an approximately cylindrical shape.

The first and second walls 158 and 159 together with the support 152 may define a space. A portion of the space may be a back pressure chamber BP.

The first wall 158 may include a top surface 158 a that defines a top surface of the first wall 158. The first wall 158 may include at least one intermediate discharge hole 158 b that communicates with the discharge hole 145 of the fixed head plate 143 to discharge the refrigerant discharged from the discharge hole 145 toward the discharge cover 105. The intermediate discharge hole 158 b may pass from a bottom surface of the first wall 158 to the top surface 158 a. An inner space of the first wall 158 having a cylindrical shape may communicate with the discharge hole 145 to define a portion of a discharge passage through which the discharged refrigerant may flow into the discharge space D.

A discharge valve 108 having an approximately circular pillar shape may be disposed inside the first wall 158. The discharge valve 108 may be disposed above the discharge hole 145 and have a size sufficient to completely cover the discharge hole 145. For example, the discharge valve 108 may have an outer diameter greater than a diameter of the discharge hole 145. Thus, when the discharge valve 108 contacts the fixed head plate 143 of the fixed scroll 140, the discharge valve 108 may close the discharge hole 145.

The discharge valve 108 may be movable in upward or downward directions according to a variation in pressure applied to the discharge valve 108. Also, the inner circumferential surface of the first wall 158 may define a moving guide 158 c that guides movement of the discharge valve 108.

A discharge pressure apply hole 158 d may be defined in the top surface 158 a of the first wall 158. The discharge pressure apply hole 158 d may communicate with the discharge hole 105 a. The discharge pressure apply hole 158 d may be defined in an approximately central portion of the top surface 158 a, and the plurality of intermediate discharge holes 158 b may be disposed to surround the discharge pressure apply hole 158 d.

For example, when operation of the scroll compressor 100 is stopped, if the refrigerant flows backward from the discharge space D toward the discharge hole 145, the pressure applied to the discharge pressure apply hole 158 d may be greater than the discharge hole-side pressure. That is, the pressure may be applied downward to a top surface of the discharge valve 108, and thus, the discharge valve 108 may move downward to close the discharge hole 145.

On the other hand, if the scroll compressor 100 operates to compress the refrigerant in the compression chamber, when the discharge hole-side pressure is greater than the pressure in the discharge space D, an upward pressure may be applied to a bottom surface of the discharge valve 108, and thus, the discharge valve 108 may move upward to open the discharge hole 145. When the discharge hole 145 is opened, the refrigerant discharged from the discharge hole 145 may flow toward the discharge cover 105 via the intermediate discharge hole 158 b, and then, may be discharged outside of the scroll compressor 100 through the discharge port 103 via the discharge hole 105 a.

The back pressure plate 150 may further include a step 158 e disposed inside a portion at which the first wall 158 and the support 152 are connected to each other. The refrigerant discharged from the discharge hole 145 may reach a space defined by the step 158 e and then flow to the intermediate discharge hole 158 b.

The second wall 159 may be spaced a predetermined distance from the first wall 158 to surround the first wall 158. The back pressure plate 150 may have a space having an approximately U-shaped cross-section formed by the first wall 158, the second wall 159, and the support 152. The floating plate 160 may be accommodated in the space. The space, which may be covered by the floating plate 160, may form the back pressure chamber BP. On the other hand, the first and second walls 158 and 159 of the back pressure plate 150, the support 152, and the floating plate 160 may define the back pressure chamber BP.

The floating plate 160 may include an inner circumferential surface that faces an outer circumferential surface of the first wall 158, and an outer circumferential surface that faces an inner circumferential surface of the second wall 159. That is, the inner circumferential surface of the floating plate 160 may contact the outer circumferential surface of the first wall 158, and the outer circumferential surface of the floating plate 160 may contact the inner circumferential surface of the second wall 159.

The floating plate 160 may have an inner diameter equal to or greater than an outer diameter of the first wall 158 of the back pressure plate 150. The floating plate 160 may have an outer diameter equal to or less than an inner diameter of the second wall 159 of the back pressure plate 150.

A sealing member 159 a to prevent the refrigerant within the back pressure chamber BP from leaking may be disposed on at least one of the first and second walls 158 and 159 and the floating plate 160. The sealing member 159 a may prevent the refrigerant from leaking between the inner circumferential surface of the second wall 159 and the outer circumferential surface of the floating plate 160. The sealing member may be disposed on the first wall 158 or the inner circumferential surface of the floating plate 160.

A contact or rib 164 that extends in an upward direction may be disposed on a top surface of the floating plate 160. For example, the contact 164 may extend in the upward direction from the inner circumferential surface of the floating plate 160.

When the floating plate 160 ascends, the contact 164 may contact a bottom surface of the discharge cover 105. When the contact 164 contacts the discharge cover 105, communication between the suction space S and the discharge space D may be blocked. On the other hand, when the contact 164 is spaced apart from the bottom surface of the discharge cover 105, that is, when the contact 164 moves in a direction away from the discharge cover 105, the suction space S and the discharge space D may communicate with each other.

In detail, while the scroll compressor 100 operates, the floating plate 160 may move upward to allow the contact 164 to contact the bottom surface of the discharge cover 105. Thus, the refrigerant discharged from the discharge hole 145 to pass through the intermediate discharge hole 158 b may not leak into the suction space S, but rather, may be discharged into the discharge space D.

On the other hand, when the scroll compressor 100 is stopped, the floating plate 160 may move downward to allow the contact 164 to be spaced apart from the bottom surface of the discharge cover 105. Thus, the discharged refrigerant disposed at the discharge cover-side may flow toward the suction space S through the space between the contact 164 and the discharge cover 105. Also, when the scroll compressor 100 is stopped, the floating plate 160 may move upward to allow the contact 164 to be spaced apart from the bottom surface of the discharge cover 105.

For example, the floating plate 160 may be formed of an aluminum material by, for example, casting. The floating plate 160 may be relatively light in comparison to other materials. Thus, when operation of the scroll compressor 100 is stopped, the floating plate 160 may quickly move downward by a pressure of the refrigerant of the discharge space D. That is, the contact 164 of the floating plate 160 may be quickly spaced apart from the discharge cover 105.

In this embodiment, the sealing member 159 a is disposed on the first wall 158 or the second wall 159 of the back pressure plate 160 and the floating plate 160. Thus, even though a descending speed of the floating plate 150 increases due to a self-weight of the floating plate 160 when the floating plate 160 is heavy, a friction force between the sealing member 159 a and the floating plate 160 may increase. As a result, the descending speed of the floating plate 160 may substantially decrease. However, according to this embodiment, as the floating plate 160 is formed of the aluminum material, the floating plate 160 may quickly descend to reduce a re-operation time of the compressor.

In this embodiment, the discharge cover 105 may be formed of a steel material, for example. In this case, a Vickers hardness (referred to as a “first hardness value”) of the discharge cover 105 may be above about 500 HV. On the other hand, a Vickers hardness (referred to as a “second hardness value”) of the floating plate 160 may be about 100 HV. That is, as the contact 164 of the floating plate 160 continuously collides with the discharge cover 105, the contact 164 may be worn out. In particular, when a liquid refrigerant is compressed, abrasion of the contact 164 may increase. In this case, the contact 164 may not block communication between the suction space S and the discharge space D.

Thus, in this embodiment, a coating layer 160 b may be disposed on at least the contact 164 on the floating plate 160. That is, the floating plate 160 may include a plate body 160 a that serves as a base material, and the coating layer 160 b disposed on at least the contact 164 on the plate body 160. Also, the coating layer 160 b may define an outer surface of the contact 164. For example, FIG. 3 illustrates the coating layer 160 b applied on an entire surface of the plate body 160.

A Vickers hardness (referred to as a “third hardness value”) of the coating layer 160 b may range from about 300 HV to about 420 HV. Thus, a difference between the Vickers hardness of the coating layer 160 b disposed on the floating plate 160 and the Vickers hardness of the discharge cover 105 may be above about 80 HV. If a difference between the Vickers hardness of the coating layer 160 b and the Vickers hardness of the discharge cover 105 is less than about 80 HV, a portion of the coating layer 160 b may be attached to the discharge cover 105, and thus, the contact 164 may be worn out while the contact 164 repeatedly collides with the discharge cover 105.

Thus, as the third hardness value of the coating layer 160 b ranges from about 300 HV to about 420 HV in this embodiment, a difference between the third hardness value of the coating layer 160 b disposed on the floating plate 160 and the first hardness value of the discharge cover 105 may be above about 80 HV to prevent the contact 164 from being worn out.

The floating body 160 a may be formed of, for example, AL6061 T6. The coating layer 160 b may include an anodizing film manufactured using, for example, an anodizing technology.

The anodizing technology may be a processing technology in which an aluminum surface is oxidized by oxygen generated from a positive electrode when power is applied to aluminum that serves as the positive electrode to form an oxidized aluminum layer. In this embodiment, the anodizing film may be formed on the floating body 160 a, for example, using a hard anodizing technology.

TABLE 1 Sample ALDC 12 Al alloy AL7075-T6 AL6061-T6 Friction coefficient 0.035 0.083 0.052 Coating thickness (μm) Soft 5~7 Soft 10 Soft 30 Straightness (μm) 80 12 1

Table 1 illustrates a friction coefficient and surface straightness according to a kind of aluminum. The AL6061-T6 may have pure aluminum of about 95% or more, and the coating using the hard anodizing technology may be effective on pure aluminum.

Thus, ALDC 12 Al alloy and AL7075-T6 may form a coating layer using a soft anodizing technology, and AL6061-T6 may form a coating layer using the hard anodizing technology.

In general, the more each of the friction coefficient and surface straightness decreases, the more abrasion performance may be improved. That is, if the surface straightness of aluminum itself is high, even though the coating layer is formed, as the surface straightness of the coating layer itself is high, abrasion may increase.

Referring to Table 1, although the friction coefficient of the ALDC 12 Al alloy is lowest, when the coating layer is formed using the hard anodizing technology, straightness of the ALDC 12 Al alloy may be high, for example, about 80. On the other hand, although the friction coefficient of the AL6061-T6 is higher than the friction coefficient of the ALDC 12 Al alloy, the AL6061-T6 may have a straightness of about 1, that is, have a very low straightness when compared to a straightness of the ALDC 12 Al alloy.

Thus, in this embodiment, the plate body 160 a may be manufactured using the AL6061-T6 having low straightness, and the coating layer 160 b may be formed using the hard anodizing technology. The plate body 160 a may have a Vickers hardness of about 110 HV or less. However, in this embodiment, the material of the plate body 160 a is not limited to the AL6061-T6. For example, the plate body 160 a may be manufactured using other aluminum alloys having low straightness and high purity.

FIG. 5 is a graph illustrating a variation in abrasion depending on a thickness of a coating layer according to an embodiment. FIG. 5 illustrates results obtained by experimentally measuring a variation in abrasion depending on a thickness of the coating layer when the plate body is manufactured using the AL6061-T6.

Referring to FIG. 5, when the coating layer is formed on the plate body formed of the AL6061-T6, and then the scroll compressor operates for a predetermined period of time (for example, about 3,500 hours), it was seen that the more the coating layer increases in thickness, the more abrasion decreases.

In the graph, if the coating layer has a thickness of about 25 μm or less, the abrasion may significantly increase above about 1 μm. Thus, this is not advantageous. Also, if the coating layer has a thickness of about 35 μm, even though the thickness does not have an influence on the abrasion, a time and cost for forming the coating layer may increase. Thus, this is not advantageous. As a result, the coating layer 160 b may have a thickness of about 25 μm to about 35 μm.

According to this embodiment, as the coating layer 160 b may be formed on the plate body 160 a to absorb an impact, abrasion of the contact 164 of the floating plate 160 may be prevented. Thus, when the scroll compressor 100 operates, communication between the suction space S and the discharge space D due to abrasion of the contact 164 may be prevented.

FIG. 6 is a perspective view of a fixed scroll according to an embodiment. Referring to FIGS. 2 and 6, the fixed scroll 140 according to an embodiment may include at least one bypass hole 149 defined in one side of the discharge hole 145.

Although two bypass holes 149 are shown in FIG. 6, embodiments are not limited to the number of bypass holes 149. The bypass holes 149 may pass through the fixed head plate 143 to extend up to the compression chamber defined by the fixed wrap 144 and the orbiting wrap 134.

The bypass hole(s) 149 may be defined in different positions according to operation conditions. For example, the bypass hole 149 may communicate with the compression chamber having a pressure greater by about 1.5 times than the suction pressure. Also, the compression chamber that communicates with the bypass hole 149 may have a pressure greater than the pressure of the compression chamber that communicates with the intermediate pressure discharge hole 147.

The scroll compressor 100 may further include a bypass valve 124 that opens and closes the bypass hole(s) 149, a stopper 220 that restricts a moving distance of the bypass valve 124 when the bypass valve 124 opens the bypass hole(s) 149, and a coupling member 230 that couples the bypass valve 124 and the stopper 220 to the fixed scroll 140 at the same time. In detail, the bypass valve 124 may include a valve support 124 a fixed to the fixed head plate 143 of the fixed scroll 140 by the coupling member 230. The bypass valve 124 may further include at least one connection portion 124 b that extends from the valve support 124 a, and at least one valve body 124 c disposed on or at a side of the connection portion 124 b. Each of the at least one connection portion 124 b and the at least one valve body 124 c may be provided in a same number as a number of the bypass hole(s) 149. For example, FIG. 5 illustrates the bypass valve 124 including two connection portions 124 b and two valve bodies 124 c.

The valve body 124 c may be maintained in contact with the top surface of the fixed head plate 143 and have a size sufficient to cover the bypass hole 149. Further, the valve body 124 c may be moved by a pressure of the refrigerant flowing along the bypass hole 149 to open the bypass hole 149. Thus, the connection portion 124 b may have a size less than a diameter of the valve body 124 c so that the valve body 124 c may smoothly move.

When the bypass valve 124 opens the bypass hole 149, the refrigerant of the compression chamber that communicates with the bypass hole 149 may flow into a space between the fixed scroll 140 and the back pressure plate 150 through the bypass hole 149 to bypass the discharge hole 145. The bypassed refrigerant may flow toward the discharge hole 105 a of the discharge cover 105 via the intermediate discharge hole 158 b.

The stopper 220 may be disposed above the bypass valve 124. The stopper 220 may have a shape corresponding to a shape of the bypass valve 124. The bypass valve 124 may be elastically deformed by the refrigerant pressure. As the stopper 220 restricts movement of the bypass valve 124, the stopper 220 may have a thickness greater than a thickness of the bypass valve 124.

The stopper 220 may include a stopper support 221 that contacts the valve support 124 a. The stopper 220 may further include at least one connection portion 225 that extends from the stopper support 221, and at least one stopper body 228 disposed on or at one side of the connection portion 225. Each of the at least one connection portion 225 of the stopper 220 and the at least one stopper body 228 may be provided in a same number as a number of the connection portions 124 b of the bypass valve 124 and the valve body 124 c.

Each connection portion 225 of the stopper 220 may be inclined in an upward direction away from the stopper support 221. Thus, the valve body 124 c may contact a top surface of the fixed head plate 143, and the stopper body 228 may be spaced apart from a top surface of the valve body 124 c in a state in which the bypass valve 124 and the stopper 220 are coupled to the fixed head plate 143 by the coupling member 230. When the valve body 124 c is lifted upward by the refrigerant flowing through the bypass hole 149, the top surface of the valve body 124 c may contact the stopper body 228, and thus, the valve body 124 c may be stopped.

Coupling holes 223 and 124 d, to which the coupling member 230 may be coupled, may be defined in the stopper support 221 and the bypass valve 124. A coupling groove 148 a, to which the coupling member 230 may be coupled, may be defined in the fixed head plate 143.

At least one guide protrusion 222 to maintain an arranged state of the coupling holes 223 and 124 d and the coupling groove 148 a before the coupling member 230 is coupled to each of the coupling holes 223 and 124 d and the coupling groove 149 a may be disposed on the stopper support 221. At least one protrusion through-hole 124 e through which the guide protrusion 222 may pass, may be defined in the valve support 221. At least one protrusion accommodation groove 148 b that accommodates the guide protrusion 222 may be defined in the fixed head plate 143. Thus, when the guide protrusion 222 of the stopper 220 is accommodated into the protrusion accommodation groove 148 b in a state in which the guide protrusion 222 passes through the protrusion through-hole 124 e of the bypass valve 124, the stopper support 221, the bypass valve 124, and each of the coupling holes 223 and 124 d and the coupling groove 149 a of the fixed head plate 143 may be aligned with each other.

The stopper 220 may include a plurality of the guide protrusion 222, the bypass valve 124 may include a plurality of the through-hole 124 e, and the fixed scroll 140 may include a plurality of the protrusion accommodation groove 148 b, so that the stopper support 221, the bypass valve 124, and the coupling holes 223 and 124 d and coupling groove 148 a of the fixed head plate 143 may be more accurately aligned with each other. In this case, the coupling groove 223 may be disposed between the plurality of guide protrusions 222 of the stopper 220. Also, the coupling groove 124 d may be disposed between the plurality of through-holes 124 e of the bypass valve 124, and the coupling groove 148 a may be disposed between the plurality of protrusion accommodation grooves 148 b of the fixed head plate 143.

The coupling member 230 may be a rivet, for example. The coupling member 230 may include a coupling body 231 coupled to the stopper support 221, the bypass valve 124, and the coupling holes 223 and 124 d and the coupling groove 148 a of the fixed head plate 143, a head 232 disposed on the coupling body 231 to contact a top surface of the stopper support 221, and a separation portion 233 that passes through the head 232, disposed inside the coupling body 231, and being separable from the coupling body 231. When the separation portion 233 is pulled upward in FIG. 5, the separation portion 233 may be separated from the coupling body 231.

According to this embodiment, a configuration and coupling method of the coupling member 230 may be realized through well-known technology, and thus, detailed description thereof has been omitted.

The intermediate pressure discharge hole 147 of the fixed scroll 140 and the intermediate pressure suction hole 153 of the back pressure plate 150 may be disposed to be aligned with each other. The refrigerant discharged from the intermediate pressure discharge hole 147 may be introduced into the back pressure chamber BP via the intermediate pressure suction hole 153. The intermediate pressure discharge hole 147 and the intermediate pressure suction hole 153 may be referred to as a “bypass passage” in that the refrigerant of the back pressure chamber BP may be bypassed to the compression chamber through the intermediate pressure discharge hole 147 and the intermediate pressure suction hole 153.

FIG. 7 is a partial view of an orbiting scroll according to an embodiment, FIG. 8 is a cross-sectional view illustrating a state in which the fixed scroll and the orbiting scroll are coupled to each other according to an embodiment. FIGS. 9A to 9C are views illustrating relative positions of an intermediate pressure discharge hole of the fixed scroll and a discharge guide of the orbiting scroll while the orbiting scroll revolves.

Referring to FIGS. 7 and 8, the orbiting scroll 130 may include a discharge guide 139 to guide the refrigerant flowing into the intermediate pressure discharge hole 147 so that the refrigerant may be introduced into a space (region) having a pressure less than a pressure of the back pressure chamber BP. In detail, when operation of the scroll compressor 100 is stopped, the compression chamber defined by the orbiting wrap 134 and the fixed wrap 144 vanishes, and thus, the refrigerant flows into the space (region) between the orbiting wrap 134 and the fixed wrap 144. The space (region) may have a pressure less than a pressure of the back pressure chamber BP. The space (region) may be referred to as a “wrap space”.

The discharge guide 139 may be recessed from an end surface of the orbiting wrap 134 of the orbiting scroll 130. Thus, the discharge guide 139 may be referred to as a “recess”. The end surface of the orbiting wrap 134 may be understood as a surface of the orbiting wrap 134 that faces the fixed head plate 143 of the fixed scroll 140 or a surface of the orbiting wrap 134 that contacts the fixed head plate 143.

A width of the end surface of the orbiting wrap 134, that is, a thickness of the orbiting wrap 134 may be greater than a width of the intermediate pressure discharge hole 147. Also, the discharge guide 139 may be recessed from the end surface of the orbiting wrap 134 by a preset or predetermined width and depth.

While the orbiting scroll 130 revolves, the orbiting wrap 134 may be disposed directly below the intermediate pressure discharge hole 147 or be disposed to be spaced horizontally from a lower end of the intermediate pressure discharge hole 147 to open the intermediate pressure discharge hole 147. If the discharge guide 139 is not provided, when the orbiting wrap 134 is disposed directly below the intermediate pressure discharge hole 147 (in FIG. 9), the orbiting wrap 134 may cover the intermediate pressure discharge hole 147. On the other hand, when the orbiting wrap 134 moves horizontally by a predetermined distance, at least a portion of the intermediate pressure discharge hole 147 may be opened. Also, while the scroll compressor 100 operates, when the intermediate pressure discharge hole 147 is opened, the intermediate pressure refrigerant of the compression chamber may be introduced into the back pressure chamber BP through the intermediate pressure discharge hole 147.

On the other hand, in a state in which the scroll compressor 100 is stopped, when the orbiting wrap 134 is disposed directly below the intermediate pressure discharge hole 147 to block the intermediate pressure discharge hole 147, the refrigerant of the back pressure chamber BP may not be introduced into the wrap space through the intermediate pressure discharge hole 147. As a result, an equilibrium pressure may not be maintained, and thus, quick re-operation of the compressor may be limited.

Thus, according to this embodiment, the discharge guide 139 may be disposed in the orbiting wrap 134 to prevent the intermediate pressure discharge hole 147 from being completely covered or shielded, and thus, even though the orbiting wrap 134 is disposed directly below the intermediate pressure discharge hole 147, the intermediate pressure discharge hole 147 and the compression chamber (when the compressor operates) or the intermediate pressure discharge hole 147 and the wrap space (when the compressor stops) may communicate with each other.

Referring to FIGS. 9A to 9C, the plurality of compression chambers is formed while the orbiting scroll 130 revolves, and then, the plurality of compression chambers moves toward the discharge hole 145 while being reduced in volume. With this process, the orbiting wrap 134 of the orbiting scroll 130 may selectively open the bypass hole 149. For example, when the orbiting wrap 134 opens the bypass hole 149, the refrigerant of the compression chamber that communicates with the bypass hole 149 may flow into the bypass hole 149 to bypass the discharge hole 145. On the other hand, when the orbiting wrap 134 covers the bypass hole 149, flow of the refrigerant of the compression chamber into the bypass hole 149 may be limited.

The back pressure chamber BP and the intermediate pressure discharge hole 147 may always communicate with the compression chamber via the discharge guide 139. That is, the discharge guide 139 may be disposed on an end of the orbiting wrap 134 at a position at which the back pressure chamber BP and the intermediate pressure discharge hole 147 always communicate with the compression chamber.

In summary, even though the orbiting wrap 134 is disposed directly below the intermediate pressure discharge hole 147 while the orbiting wrap 134 revolves, the lower end of the intermediate pressure discharge hole 147 and the end surface of the orbiting wrap 134 may be spaced apart from each other by the recessed discharge guide 139. Thus, when the scroll compressor 100 operates, refrigerant of the compression chamber may be introduced into the back pressure chamber BP through the intermediate pressure discharge hole 147. Also, when the scroll compressor 100 is stopped, the refrigerant of the back pressure chamber BP may be introduced into the wrap space through the intermediate pressure discharge hole 147.

In detail, FIGS. 9A to 9C illustrate a state in which the orbiting wrap 134 is disposed directly below the intermediate pressure discharge hole 147 while the orbiting wrap 134 revolves, that is, the state in which the end surface of the orbiting wrap 134 is disposed to block the intermediate pressure discharge hole 147 if the discharge guide 139 is not provided. Even though the orbiting wrap 134 is disposed as illustrated in FIGS. 9A to 9C, the intermediate pressure discharge hole 147 may communicate with the compression chamber by the discharge guide 139. Thus, the refrigerant of the back pressure chamber BP having an intermediate pressure Pm may be introduced into the wrap space between the orbiting wrap 134 and the fixed wrap 144 via the intermediate pressure discharge hole 147 and the discharge guide 139.

If the orbiting wrap 134 is disposed at a position not illustrated in FIGS. 9A to 9C, at least a portion of the intermediate pressure discharge hole 147 may be opened. That is, the orbiting wrap 134 may be in a state in which the orbiting wrap 134 moves horizontally to open the at least a portion of the lower end of the intermediate pressure discharge hole 147.

FIG. 10 is a partial cross-sectional view of a scroll compressor according to another embodiment. This embodiment may be the same as the previous embodiment except for a structure of a discharge cover. Thus, only characterized parts in this embodiment will be described hereinbelow, and repetitive disclosure has been omitted.

Referring to FIG. 10, discharge cover 105 according to this embodiment may include an impact absorption layer 109 on a portion (for example, a bottom surface of the discharge cover 105 in FIG. 10) of floating plate 160 that faces contact 164. A groove 107 that accommodates the impact absorption layer 109 may be defined in the discharge cover 105.

The impact absorption layer 109 may be formed of, for example, a Teflon material. More particularly, the impact absorption layer 109 may be formed of a poly tetra fluoro ethylene (PTFE) material, for example. The PTFE may be sprayed onto the groove 107 of the discharge cover 105 in a fluoride resin formed in a paint form to perform a heating and plasticizing process on the applied fluoride resin at a predetermined temperature, thereby forming an inactive coating layer.

When the scroll compressor 100 operates and the floating plate 160 ascends by an intermediate pressure of back pressure chamber BP, the contact 164 (substantially, the coating layer 160 b) of the floating plate 160 may contact the impact absorption layer 109.

If the impact absorption layer 109 is formed of Teflon, the impact absorption layer 109 may have a low Vickers hardness of about 15 HV, which is relatively soft when compared to the discharge cover 105. Thus, the Teflon may not be broken and absorb an impact applied to the contact 164. Also, as the coating layer 160 a of the contact 164 may have a hardness value greater than a hardness value of the impact absorption layer 109, abrasion of the contact 164 may also be prevented. To effectively absorb the impact through the impact absorption layer 109, the impact absorption layer 109 may have a thickness of about 50 μm or more.

Although the impact absorption layer 109 may be disposed in the groove 107 of the discharge cover 105 in this embodiment, embodiments are not limited thereto. For example, the impact absorption layer 109 may be applied to a portion of the floating plate 160 that faces the contact 164 on the discharge cover 105, a portion of the discharge cover 105 that faces the floating plate 160, or an entire bottom surface of the discharge cover 105.

Embodiments disclosed herein provide a scroll compressor.

Embodiments disclosed herein provide a scroll compressor that may include a casing including a rotational shaft; a discharge cover fixed inside of the casing to partition the inside of the casing into a suction space and a discharge space; a first scroll that is revolved by rotation of the rotational shaft; a second scroll that defines a plurality of compression chambers together with the first scroll, the second scroll having an intermediate pressure discharge hole that communicates with a compression chamber having an intermediate pressure of the plurality of compression chambers; a back pressure plate that defines a back pressure chamber that accommodates a refrigerant discharged from the intermediate pressure discharge hole; a floating plate movably disposed on or at a side of the back pressure plate to define the back pressure chamber together with the back pressure plate, the floating plate including a contact part or contact that is capable of contacting the discharge cover; and a coating layer that defines an outer surface of the contact part. The discharge cover may have a first hardness value, the floating plate may have a second hardness value, and the coating layer may have a third hardness value. The third hardness value may be less than the first hardness value and greater than the second hardness value.

Embodiments disclosed herein further provide a scroll compressor that may include a casing including a rotational shaft; a discharge cover fixed inside of the casing to partition the inside of the casing into a suction space and a discharge space; a first scroll that is revolved by rotation of the rotational shaft; a second scroll that defines a plurality of compression chambers together with the first scroll, the second scroll having an intermediate pressure discharge hole that communicates with a compression chamber having an intermediate pressure of the plurality of compression chambers; a back pressure plate that defines a back pressure chamber that accommodates a refrigerant discharged from the intermediate pressure discharge hole; a floating plate movably disposed on or at a side of the back pressure plate to define the back pressure chamber together with the back pressure plate, the floating plate including a contact part or contact that is capable of contacting the discharge cover; a coating layer that defines an outer surface of the contact part; and an impact absorption layer disposed on a portion of the discharge cover facing the contact part.

The details of one or more embodiments are set forth in the accompanying drawings and the description. Other features will be apparent from the description and drawings, and from the claims.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. 

What is claimed is:
 1. A scroll compressor, comprising: a casing comprising a rotational shaft; a discharge cover fixed inside of the casing to partition the inside of the casing into a suction space and a discharge space; a first scroll that is revolved by rotation of the rotational shaft; a second scroll that defines a plurality of compression chambers together with the first scroll, the second scroll having an intermediate pressure discharge hole that communicates with a compression chamber having an intermediate pressure of the plurality of compression chambers; a back pressure plate that defines a back pressure chamber that accommodates a refrigerant discharged from the intermediate pressure discharge hole; a floating plate movably disposed on or at a side of the back pressure plate to define the back pressure chamber together with the back pressure plate, the floating plate comprising a contact capable of contacting the discharge cover; and a coating layer that defines an outer surface of the contact, wherein the discharge cover has a first hardness value, the floating plate has a second hardness value, and the coating layer has a third hardness value, and wherein the third hardness value is less than the first hardness value and greater than the second hardness value.
 2. The scroll compressor according to claim 1, wherein the floating plate is formed of an aluminum material, and the coating layer comprises an anodizing film.
 3. The scroll compressor according to claim 2, wherein the coating layer has a thickness of about 25 μm to about 35 μm.
 4. The scroll compressor according to claim 1, wherein a difference between the first hardness value and the third hardness value is above about 80 HV.
 5. The scroll compressor according to claim 1, wherein the first hardness value is above about 500 HV, the second hardness value is below about 110 HV, and the third hardness value ranges from about 300 HV to about 420 HV.
 6. The scroll compressor according to claim 1, wherein the coating layer is formed on an entire outer circumferential surface of the floating plate.
 7. The scroll compressor according to claim 1, wherein a discharge guide that guides discharge of a refrigerant within the back pressure chamber is disposed on the first scroll or the second scroll.
 8. The scroll compressor according to claim 1, wherein the discharge cover comprises an impact absorption layer disposed at a portion thereof that faces the contact.
 9. The scroll compressor according to claim 8, wherein the coating layer has a hardness value greater than a hardness value of the impact absorption layer.
 10. The scroll compressor according to claim 8, wherein the impact absorption layer is formed of a Teflon material.
 11. The scroll compressor according to claim 8, wherein the impact absorption layer is applied to the discharge cover or inserted into a groove formed in the discharge cover.
 12. The scroll compressor according to claim 1, wherein the contact comprises a rib that extends along an inner circumference of the floating plate.
 13. The scroll compressor according to claim 1, wherein the first scroll comprises an orbiting scroll and the second scroll comprises a fixed scroll.
 14. A scroll compressor, comprising: a casing comprising a rotational shaft; a discharge cover fixed inside of the casing to partition the inside of the casing into a suction space and a discharge space; a first scroll that is revolved by rotation of the rotational shaft; a second scroll that defines a plurality of compression chambers together with the first scroll, the second scroll having an intermediate pressure discharge hole that communicates with a compression chamber having an intermediate pressure of the plurality of compression chambers; a back pressure plate that defines a back pressure chamber that accommodates a refrigerant discharged from the intermediate pressure discharge hole; a floating plate movably disposed on or at a side of the back pressure plate to define the back pressure chamber together with the back pressure plate, the floating plate comprising a contact capable of contacting the discharge cover; a coating layer that defines an outer surface of the contact; and an impact absorption layer disposed on a portion of the discharge cover that faces the contact.
 15. The scroll compressor according to claim 14, wherein the coating layer has a hardness value greater than a hardness value of the impact absorption layer.
 16. The scroll compressor according to claim 14, wherein the impact absorption layer is formed of a Teflon material.
 17. The scroll compressor according to claim 14, wherein the discharge cover comprises a groove that accommodates the impact absorption layer.
 18. The scroll compressor according to claim 14, wherein the impact absorption layer is applied to a surface of the discharge cover that faces the back pressure plate.
 19. The scroll compressor according to claim 14, wherein the impact absorption layer has a thickness thicker than a thickness of the coating layer.
 20. The scroll compressor according to claim 19, wherein the impact absorption layer has a thickness of about 50 μm.
 21. The scroll compressor according to claim 19, wherein the coating layer has a thickness of about 25 μm to about 35 μm.
 22. The scroll compressor according to claim 14, wherein the floating plate is formed of an aluminum material, and the coating layer comprises an anodizing film.
 23. The scroll compressor according to claim 14, wherein the contact comprises a rib that extends along an inner circumference of the floating plate.
 24. The scroll compressor according to claim 14, wherein the first scroll comprises an orbiting scroll and the second scroll comprises a fixed scroll.
 25. A scroll compressor, comprising: a casing comprising a rotational shaft; a discharge cover fixed inside of the casing to partition the inside of the casing into a suction space and a discharge space; an orbiting scroll that is revolved by rotation of the rotational shaft; a fixed scroll that defines a plurality of compression chambers together with the orbiting scroll, the fixed scroll having an intermediate pressure discharge hole that communicates with a compression chamber having an intermediate pressure of the plurality of compression chambers; a back pressure plate that defines a back pressure chamber that accommodates a refrigerant discharged from the intermediate pressure discharge hole; a floating plate movably disposed on or at a side of the back pressure plate to define the back pressure chamber together with the back pressure plate, the floating plate comprising a rib capable of contacting the discharge cover, wherein the rib is disposed at an upper surface of the floating plate; and a coating layer provided at an outer surface of the rib, wherein the discharge cover has a first hardness value, the floating plate has a second hardness value, and the coating layer has a third hardness value, and wherein the third hardness value is less than the first hardness value and greater than the second hardness value. 